Flannan may refer to:

Flannán mac Toirrdelbaig, saint and patron of Killaloe Flannan Isles, a small island group in the Outer Hebrides of Scotland Flannan Isles Lighthouse, lighthouse on Eilean Mòr, one of the Flannan Isles St Flannan's College, Irish secondary school Flannan Isle, poem by Wilfrid Wilson Gibson